The initiative to reduce all roaming charges has been championed by Viviane Reding, the European Commissioner overseeing telecoms. On her watch, mobile operators have seen their revenues from the estimated €8.5 billion ($11.5 billion) roaming market slashed, the FT says.

In addition to reduced charges, operators will be obliged to secure their customers' express agreement when they reach certain limits before they continue using services. This is because there have been instances of users unwittingly running up bills for thousands of euros, for instance because of a huge download in background mode.

Under the proposed legislation, the wholesale price of downloading one megabyte of data would be capped at €1 by July 1, falling to 50 cents in two years' time. Cross-border text messages would cost no more than 11 cents, down from a 29 cent European average today. Making roaming voice calls would also become gradually cheaper, falling from 46 cents today to 25 cents in July 2011.

The agreement also calls for billing to be made by the second, a move that alone could deprive operators of one quarter of their voice roaming charges, according to the Commission. Operators would be allowed to charge the equivalent of 30 seconds as a minimum charge, however.